I agree...  it is a good idea to wash the mattress covers and hang
them to air dry.  however, i will add that it took me over an hour to
get the cover back on the large foam that goes over the engine.

so, not wanting to repeat this experience too soon, i had a nice
flannel sheet altered to fit the mattress...  keeps it clean and
improves the comfort level a hundred times!!  cost about $10 and an
old sheet.

Ben.